Fix minibuffer window related docs and strings (Bug#28978)

* src/frame.c (Vdefault_minibuffer_frame): Fix doc-string.
* src/window.c (Fminibuffer_selected_window): Fix doc-string.
* doc/lispref/frames.texi (Buffer Parameters): Rewrite
description of `minibuffer' parameter.
* doc/lispref/minibuf.texi (Minibuffer Windows): Reorder
entries and partly rewrite section.
(Minibuffer Misc): Clarify description of
`minibuffer-selected-window'.
* etc/NEWS: Mention new semantics of 'minibuffer' frame
parameter.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/window.c b/src/window.c
index ba86d73911f..f08979e1320 100644
--- a/src/window.c
+++ b/src/window.c
@@ -5833,7 +5833,7 @@ by this function.  This happens in an interactive call.  */)
 
 DEFUN ("minibuffer-selected-window", Fminibuffer_selected_window, Sminibuffer_selected_window, 0, 0, 0,
        doc: /* Return the window which was selected when entering the minibuffer.
-Returns nil, if selected window is not a minibuffer window.  */)
+Return nil if the selected window is not a minibuffer window.  */)
   (void)
 {
   if (minibuf_level > 0